Anatomy Vocab ch6 pt2

Light (I) bands

A light band across a striated muscle fiber that consists of actin

Dark (A) bands

One of the cross striations in striated muscle that contain myosin and appear dark

Action potential

an electrical event occurring when a stimulus of sufficient intensity is applied to a neuron or muscle cell allowing sodium ions to move into the cell and resume the polarity

Graded responses

a response that varies directly with the strength of the stimulus

Muscle twitches

a single rapid contraction of a muscle followed by relaxation

Unfused tetanus

When the muscle is stimu-lated so rapidly that no evidence of relaxationis seen and the contractions are completelysmooth and sustained

Incomplete tetanus

muscle contraction in which the muscle does not completely relax between stimulation events; causes an increase in force because individual twitches are added together, or summed

Direct phosphorylation

the addition of a phosphate (PO43−) group to a protein or other organic molecule

Creatine phosphate (CP)

a compound that transfers a phosphate group to ADP to regenerate ATP in muscle fibers

Aerobic pathway

requires oxygen to produce ATP, because carbohydrates and fats are only burned in the presence of oxygen

Aerobic respiration

the process most living things undergo to use food energy

Anaerobic glycolysis and lactic acid formation

involves the breakdown of glucose to pyruvic acid (pyruvate) and, subsequently, to lactic acid (lactate)

Lactic acid

the product of anaerobic metabolism, especially in muscle

Anaerobic glycolysis

a metabolic process that generates energy for cells when oxygen is limited

Muscle fatigue

Inability of a muscle to contract even when being stimulated

Oxygen deficit

the volume of oxygen required after exercise to oxidize the lactic acid formed during exercise

Isotonic contractions

refers to "same tone"; the muscle shortens as it contracts, and movement occurs

Isometric contractions

refers to "same length" the muscle generates tension but does not shorten and no movement occurs

Muscle tone

sustained partial contraction of a muscle in response to stretch receptor inputs; keeps the muscle healthy and ready to react

Flaccid

lacking firmness or muscle tone, or being soft and yielding

Atrophy

reduction in size or wasting away of an organ or cell resulting from disease or lack of use

Aerobic/endurance exercise

Process that requires oxygen

Resistance/isometric exercise

a type of resistance exercise that involves contracting a muscle or group of muscles without changing their length

Origin

immovable (less movable) bone

Insertion

The attachment of a muscle tendon to a movable bone

Antagonists

Muscle that opposes or reverses a prime mover

Synergists

muscle that aids a prime mover in a movement and helps prevent rotation

Fixators

a muscle that stabilizes a body part to allow other muscles to move it from a stable base.

Circular

refer to muscles, folds, or layers of the body that form a circle

Convergent

a muscle that has a wide area of expansion and a single attachment point

Parallel

fascicles run parallel to the long axis of a muscle

Fusiform

having a spindle shape, or being wide in the middle and tapering at the ends

Pennate

muscles with fibers that are arranged at an angle to the muscle's line of action

Prime Mover

The muscle that acts as the initial and main source of motive power